SOTOMAYOR, J., announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I, II–A, II–B, and IV, in which SCALIA, KENNEDY, GINSBURG, and KAGAN, JJ., joined, and an opinion with respect to Parts II–C and III, in which SCALIA, GINSBURG, and KAGAN, JJ., joined.
II – B
The State properly recognizes that the reasonableness of a warrantless search under the exigency exception to the warrant requirement must be evaluated based on the totality of the circumstances. Brief for Petitioner 28–29. But the State nevertheless seeks a per se rule for blood testing in drunk-driving cases. The State contends that whenever an officer has probable cause to believe an individual has been driving under the influence of alcohol, exigent circumstances will necessarily exist because BAC evidence is inherently evanescent. As a result, the State claims that so long as the officer has probable cause and the blood test is conducted in a reasonable manner, it is categorically reasonable for law enforcement to obtain the blood sample without a warrant.
. . . .
But it does not follow that we should depart from careful case-by-case assessment of exigency and adopt the categorical rule proposed by the State and its amici. In those drunk-driving investigations where police officers can reasonably obtain a warrant before a blood sample can be drawn without significantly undermining the efficacy of the search, the Fourth Amendment mandates that they do so. . . . We do not doubt that some circumstances will make obtaining a warrant impractical such that the dissipation of alcohol from the bloodstream will support an exigency justifying a properly conducted warrantless blood test. That, however, is a reason to decide each case on its facts, as we did in Schmerber, not to accept the “considerable overgeneralization” that a per se rule would reflect. Richards, 520 U. S., at 393.
The context of blood testing is different in critical respects from other destruction-of-evidence cases in which the police are truly confronted with a “‘now or never’” situation. Roaden v. Kentucky, 413 U. S. 496, 505 (1973). In contrast to, for example, circumstances in which the suspect has control over easily disposable evidence, see Georgia v. Randolph, 547 U. S. 103, 116, n. 6 (2006); Cupp, 412 U. S., at 296, BAC evidence from a drunk driving suspect naturally dissipates over time in a gradual and relatively predictable manner. Moreover, because a police officer must typically transport a drunk-driving suspect to a medical facility and obtain the assistance of someone with appropriate medical training before conducting a blood test, some delay between the time of the arrest or accident and the time of the test is inevitable regardless of whether police officers are required to obtain a warrant. See State v. Shriner, 751 N. W. 2d 538, 554 (Minn. 2008) (Meyer, J., dissenting). This reality undermines the force of the State’s contention, endorsed by the dissent, see post, at 3 (opinion of THOMAS, J.), that we should recognize a categorical exception to the warrant requirement because BAC evidence “is actively being destroyed with every minute that passes.” Brief for Petitioner 27. Consider, for example, a situation in which the warrant process will not significantly increase the delay before the blood test is conducted because an officer can take steps to secure a warrant while the suspect is being transported to a medical facility by another officer. In such a circumstance, there would be no plausible justification for an exception to the warrant requirement.
The State’s proposed per se rule also fails to account for advances in the 47 years since Schmerber was decided that allow for the more expeditious processing of warrant applications, particularly in contexts like drunk-driving investigations where the evidence offered to establish probable cause is simple. . . . Well over a majority of States allow police officers or prosecutors to apply for search warrants remotely through various means, including telephonic or radio communication, electronic communication such as e-mail, and video conferencing.4 [Footnote cites, inter alia, Ind. Code § 35-33-5-8.] And in addition to technology-based developments, jurisdictions have found other ways to streamline the warrant process, such as by using standard-form warrant applications for drunk driving investigations. [Footnote omitted.]
We by no means claim that telecommunications innovations have, will, or should eliminate all delay from the warrant-application process. Warrants inevitably take some time for police officers or prosecutors to complete and for magistrate judges to review. Telephonic and electronic warrants may still require officers to follow time consuming formalities designed to create an adequate record, such as preparing a duplicate warrant before calling the magistrate judge. See Fed. Rule Crim. Proc. 4.1(b)(3). And improvements in communications technology do not guarantee that a magistrate judge will be available when an officer needs a warrant after making a late night arrest. But technological developments that enable police officers to secure warrants more quickly, and do so without undermining the neutral magistrate judge’s essential role as a check on police discretion, are relevant to an assessment of exigency. That is particularly so in this context, where BAC evidence is lost gradually and relatively predictably. [Footnote omitted.]
Of course, there are important countervailing concerns. While experts can work backwards from the BAC at the time the sample was taken to determine the BAC at the time of the alleged offense, longer intervals may raise questions about the accuracy of the calculation. For that reason, exigent circumstances justifying a warrantless blood sample may arise in the regular course of law enforcement due to delays from the warrant application process. But adopting the State’s per se approach would improperly ignore the current and future technological developments in warrant procedures, and might well diminish the incentive for jurisdictions “to pursue progressive approaches to warrant acquisition that preserve the protections afforded by the warrant while meeting the legitimate interests of law enforcement.” State v. Rodriguez, 2007 UT 15, ¶46, 156 P. 3d 771, 779.
In short, while the natural dissipation of alcohol in the blood may support a finding of exigency in a specific case, as it did in Schmerber, it does not do so categorically. Whether a warrantless blood test of a drunk-driving suspect is reasonable must be determined case by case based on the totality of the circumstances.
JUSTICE KENNEDY, concurring in part:
. . . The repeated insistence . . . that every case be determined by its own circumstances is correct, of course, as a general proposition; yet it ought not to be interpreted to indicate this question is not susceptible of rules and guidelines that can give important, practical instruction to arresting officers, instruction that in any number of instances would allow a warrantless blood test in order to preserve the critical evidence.
States and other governmental entities which enforce the driving laws can adopt rules, procedures, and protocols that meet the reasonableness requirements of the Fourth Amendment and give helpful guidance to law enforcement officials. And this Court, in due course, may find it appropriate and necessary to consider a case permitting it to provide more guidance than it undertakes to give today.
CHIEF JUSTICE ROBERTS, with whom JUSTICE BREYER and JUSTICE ALITO join, concurring in part and dissenting in part:
A police officer reading this Court’s opinion would have no idea—no idea—what the Fourth Amendment requires of him, once he decides to obtain a blood sample from a drunk driving suspect who has refused a breathalyzer test. I have no quarrel with the Court’s “totality of the circumstances” approach as a general matter; that is what our cases require. But the circumstances in drunk driving cases are often typical, and the Court should be able to offer guidance on how police should handle cases like the one before us.
In my view, the proper rule is straightforward. Our cases establish that there is an exigent circumstances exception to the warrant requirement. That exception applies when there is a compelling need to prevent the imminent destruction of important evidence, and there is no time to obtain a warrant. The natural dissipation of alcohol in the bloodstream constitutes not only the imminent but ongoing destruction of critical evidence. That would qualify as an exigent circumstance, except that there may be time to secure a warrant before blood can be drawn. If there is, an officer must seek a warrant. If an officer could reasonably conclude that there is not, the exigent circumstances exception applies by its terms, and the blood may be drawn without a warrant.
JUSTICE THOMAS, dissenting.
This case requires the Court to decide whether the Fourth Amendment prohibits an officer from obtaining a blood sample without a warrant when there is probable cause to believe that a suspect has been driving under the influence of alcohol. Because the body’s natural metabolization of alcohol inevitably destroys evidence of the crime, it constitutes an exigent circumstance. As a result, I would hold that a warrantless blood draw does not violate the Fourth Amendment.